An access network that provides air-interface service under an air-interface protocol such as WiMAX, or other air-interface protocols such as 1xRTT (Single Carrier Radio Transmission Technology) CDMA (Code Division Multiple Access), EV-DO (Evolution Data Optimized), WiFi (e.g. IEEE 802.11), GSM (Global System for Mobile Communications), etc., may include a number of base stations that provide service in one or more coverage areas of the access network. In order to provide substantially continuous service, base stations may be configured to perform a handoff, transferring a connection from one base station to another as a user moves from one coverage area to another in the access network.
Under certain air-interface protocols, such as WiMAX and CDMA, a connection between a mobile station and an access network may include two connections: (1) an uplink (or forward-link) connection over which the mobile station sends data to the access network and (2) a downlink (or reverse-link) connection over which the mobile station receives data from the access network. Thus, when a handoff is performed from one base station to another, or from one coverage area to another, the handoff involves transfer of both the uplink and downlink connections from the originating or “source” base station to a “target” base station.